1. Field of the Invention
The present invention relates to a heat-sensitive recording sheet and more particularly, to a heat-sensitive recording sheet improved in color formability and sticking resistance and excellent in image stabilities such as plasticizer resistance and water resistance and in printability.
2. Related Art
Recently, heat-sensitive recording sheets which form a color by application of heat are widely used for facsimile, word processors, plotter systems, labeling and the like. This is because the printing system comprises forming color images by an instantaneous chemical reaction with heating and has the advantages such as use of small devices, high recording speed, little noise and environmental pollution and low cost. However, in the case of customarily employed heat-sensitive recording systems which use dye precursors and electron-accepting compounds as color forming components, the white portions of the recording sheet sometimes develop color with organic solvents such as toluene and methyl ethyl ketone, and decoloration of the color formed portions sometimes occurs when the sheet comes to contact with a hair dressing, dibutyl mentioned technics, the utilization of not only high speed and wideband characteristics, as distinctive features of optical signals, but also of wavelength division multiplexing technology is possible. In the technics, wavelength are used as routing information, and the signals are converted and classified to wavelength groups corresponding to respective outgoing lines.
Further, an optical ATM switching system having a self-routing switch is proposed in which an input signal of predetermined wavelength having input information is converted to a signal of a wavelength having the routing information and the input information is outputted to a desired output terminal by self-routing based on the routing information contained in the signal of the wavelength, as an optical ATM switching system as shown in JP-A-104148.
In a conventional system as shown in the former well-known example, however, even though wavelengths are used as routing information, degree of multiplexing of a speech path is not upgraded. Therefore, even when wavelength division multiplexing is adopted for upgrading the degree of multiplexing of a speech path, a means for splitting cells from multiplexed data is left out of consideration.
When the cells arriving from respective transmission lines at different times are synchronized, it is considered to utilize optical memories, which requires, however, to monitor the phases of cells from all incoming transmission lines and to synchronize them, so that complicated processes and circuits are needed.
Further, a small-sized and inexpensive optical memory like an electrical memory will not be available for some time to come. Therefore, it is required to use an optical memory or the like efficiently by making the most of the features of optical signals that wavelength division multiplexing may be utilized.
Further, also in the case of JP-A-104148, because of the utilization of wavelengths for routing information, a complicated wavelength detector is needed to discriminate output routes, and a means for splitting cells from wavelength division multiplexed data is not mentioned similarly to the case of the former well-known example.